In 2008, Virgin Galactic first promised sub-orbital spaceflight trips for tourists would be taking place “within 18 months”. It has since regularly made similar promises to have space flights airborne in the near future.

But delays and a fatal crash in 2014 prevented Sir Richard’s original ambitions.

On Thursday, the SpaceShipTwo passenger rocket ship took off from the Mojave Desert in California.

The company said the space ship’s motor burned for 60 seconds, travelling at 2.9 times the speed of sound as it gained height.

The rocket carried two pilots and a mannequin named Annie as a stand-in passenger, as well as four research experiments for NASA.

It did not breach the 100km Karman Line, where Earth’s atmosphere ends.

“Today we have shown Virgin Galactic can open space to the world,” Sir Richard said.

While the trip marked a milestone for Virgin Galactic, the firm’s rivals have already ventured deeper into space – albeit without humans on board.

SpaceX, in partnership with NASA, is planning crewed missions for early next year. Mr Bezos has also said Blue Origin plans to send its first crew to space in 2019.

Sir Richard said he aimed for a commercial space flight with passengers – including himself – by March 2019

Virgin Galactic, which is charging $250,000 for a 90-minute flight, has said more than 600 people have bought tickets or put down deposits for an eventual voyage.